#!/usr/bin/python

# Copyright (c) 2013, David Stygstra <david.stygstra@gmail.com>
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later

from __future__ import annotations

DOCUMENTATION = r"""
module: modprobe
short_description: Load or unload kernel modules
author:
  - David Stygstra (@stygstra)
  - Julien Dauphant (@jdauphant)
  - Matt Jeffery (@mattjeffery)
description:
  - Load or unload kernel modules.
extends_documentation_fragment:
  - community.general.attributes
attributes:
  check_mode:
    support: full
  diff_mode:
    support: none
options:
  name:
    type: str
    required: true
    description:
      - Name of kernel module to manage.
  state:
    type: str
    description:
      - Whether the module should be present or absent.
    choices: [absent, present]
    default: present
  params:
    type: str
    description:
      - Modules parameters.
    default: ''
  persistent:
    type: str
    choices: [disabled, absent, present]
    default: disabled
    version_added: 7.0.0
    description:
      - Persistency between reboots for configured module.
      - This option creates files in C(/etc/modules-load.d/) and C(/etc/modprobe.d/) that make your module configuration persistent
        during reboots.
      - If V(present), adds module name to C(/etc/modules-load.d/) and params to C(/etc/modprobe.d/) so the module is loaded
        on next reboot.
      - If V(absent), comments out module name from C(/etc/modules-load.d/) and comments out params from C(/etc/modprobe.d/)
        so the module is not loaded on next reboot.
      - If V(disabled), does not touch anything and leaves C(/etc/modules-load.d/) and C(/etc/modprobe.d/) as it is.
      - Note that it is usually a better idea to rely on the automatic module loading by PCI IDs, USB IDs, DMI IDs or similar
        triggers encoded in the kernel modules themselves instead of configuration like this.
      - In fact, most modern kernel modules are prepared for automatic loading already.
      - B(Note:) This option works only with distributions that use C(systemd) when set to values other than V(disabled).
"""

EXAMPLES = r"""
- name: Add the 802.1q module
  community.general.modprobe:
    name: 8021q
    state: present

- name: Add the dummy module
  community.general.modprobe:
    name: dummy
    state: present
    params: 'numdummies=2'

- name: Add the dummy module and make sure it is loaded after reboots
  community.general.modprobe:
    name: dummy
    state: present
    params: 'numdummies=2'
    persistent: present
"""

import os.path
import platform
import shlex
import traceback
import re

from ansible.module_utils.basic import AnsibleModule

RELEASE_VER = platform.release()
MODULES_LOAD_LOCATION = "/etc/modules-load.d"
PARAMETERS_FILES_LOCATION = "/etc/modprobe.d"


class Modprobe:
    def __init__(self, module):
        self.module = module
        self.modprobe_bin = module.get_bin_path("modprobe", True)

        self.check_mode = module.check_mode
        self.desired_state = module.params["state"]
        self.name = module.params["name"]
        self.params = module.params["params"]
        self.persistent = module.params["persistent"]

        self.changed = False

        self.re_find_module = re.compile(rf"^ *{self.name} *(?:[#;].*)?\n?\Z")
        self.re_find_params = re.compile(rf"^options {self.name} \w+=\S+ *(?:[#;].*)?\n?\Z")
        self.re_get_params_and_values = re.compile(rf"^options {self.name} (\w+=\S+) *(?:[#;].*)?\n?\Z")

    def load_module(self):
        command = [self.modprobe_bin]
        if self.check_mode:
            command.append("-n")
        command.extend([self.name] + shlex.split(self.params))

        rc, out, err = self.module.run_command(command)

        if rc != 0:
            return self.module.fail_json(msg=err, rc=rc, stdout=out, stderr=err, **self.result)

        if self.check_mode or self.module_loaded():
            self.changed = True
        else:
            rc, stdout, stderr = self.module.run_command(
                [self.modprobe_bin, "-n", "--first-time", self.name] + shlex.split(self.params)
            )
            if rc != 0:
                self.module.warn(stderr)

    @property
    def module_is_loaded_persistently(self):
        for module_file in self.modules_files:
            with open(module_file) as file:
                for line in file:
                    if self.re_find_module.match(line):
                        return True

        return False

    @property
    def params_is_set(self):
        desired_params = set(self.params.split())

        return desired_params == self.permanent_params

    @property
    def permanent_params(self):
        params = set()

        for modprobe_file in self.modprobe_files:
            with open(modprobe_file) as file:
                for line in file:
                    match = self.re_get_params_and_values.match(line)
                    if match:
                        params.add(match.group(1))

        return params

    def create_module_file(self):
        file_path = os.path.join(MODULES_LOAD_LOCATION, f"{self.name}.conf")
        if not self.check_mode:
            with open(file_path, "w") as file:
                file.write(f"{self.name}\n")

    @property
    def module_options_file_content(self):
        file_content = "\n".join([f"options {self.name} {param}" for param in self.params.split()])
        return f"{file_content}\n"

    def create_module_options_file(self):
        new_file_path = os.path.join(PARAMETERS_FILES_LOCATION, f"{self.name}.conf")
        if not self.check_mode:
            with open(new_file_path, "w") as file:
                file.write(self.module_options_file_content)

    def disable_old_params(self):
        for modprobe_file in self.modprobe_files:
            with open(modprobe_file) as file:
                file_content = file.readlines()

            content_changed = False
            for index, line in enumerate(file_content):
                if self.re_find_params.match(line):
                    file_content[index] = f"#{line}"
                    content_changed = True

            if not self.check_mode and content_changed:
                with open(modprobe_file, "w") as file:
                    file.write("\n".join(file_content))

    def disable_module_permanent(self):
        for module_file in self.modules_files:
            with open(module_file) as file:
                file_content = file.readlines()

            content_changed = False
            for index, line in enumerate(file_content):
                if self.re_find_module.match(line):
                    file_content[index] = f"#{line}"
                    content_changed = True

            if not self.check_mode and content_changed:
                with open(module_file, "w") as file:
                    file.write("\n".join(file_content))

    def load_module_permanent(self):
        if not self.module_is_loaded_persistently:
            self.create_module_file()
            self.changed = True

        if not self.params_is_set:
            self.disable_old_params()
            self.create_module_options_file()
            self.changed = True

    def unload_module_permanent(self):
        if self.module_is_loaded_persistently:
            self.disable_module_permanent()
            self.changed = True

        if self.permanent_params:
            self.disable_old_params()
            self.changed = True

    @property
    def modules_files(self):
        if not os.path.isdir(MODULES_LOAD_LOCATION):
            return []
        modules_paths = [os.path.join(MODULES_LOAD_LOCATION, path) for path in os.listdir(MODULES_LOAD_LOCATION)]
        return [path for path in modules_paths if os.path.isfile(path)]

    @property
    def modprobe_files(self):
        if not os.path.isdir(PARAMETERS_FILES_LOCATION):
            return []
        modules_paths = [
            os.path.join(PARAMETERS_FILES_LOCATION, path) for path in os.listdir(PARAMETERS_FILES_LOCATION)
        ]
        return [path for path in modules_paths if os.path.isfile(path)]

    def module_loaded(self):
        is_loaded = False
        try:
            with open("/proc/modules") as modules:
                module_name = f"{self.name.replace('-', '_')} "
                for line in modules:
                    if line.startswith(module_name):
                        is_loaded = True
                        break

            if not is_loaded:
                module_file = f"/{self.name}.ko"
                builtin_path = os.path.join("/lib/modules/", RELEASE_VER, "modules.builtin")
                with open(builtin_path) as builtins:
                    for line in builtins:
                        if line.rstrip().endswith(module_file):
                            is_loaded = True
                            break
        except (IOError, OSError) as e:
            self.module.fail_json(msg=f"{e}", exception=traceback.format_exc(), **self.result)

        return is_loaded

    def unload_module(self):
        command = [self.modprobe_bin, "-r", self.name]
        if self.check_mode:
            command.append("-n")

        rc, out, err = self.module.run_command(command)
        if rc != 0:
            return self.module.fail_json(msg=err, rc=rc, stdout=out, stderr=err, **self.result)

        self.changed = True

    @property
    def result(self):
        return {
            "changed": self.changed,
            "name": self.name,
            "params": self.params,
            "state": self.desired_state,
        }


def build_module():
    return AnsibleModule(
        argument_spec=dict(
            name=dict(type="str", required=True),
            state=dict(type="str", default="present", choices=["absent", "present"]),
            params=dict(type="str", default=""),
            persistent=dict(type="str", default="disabled", choices=["disabled", "present", "absent"]),
        ),
        supports_check_mode=True,
    )


def main():
    module = build_module()

    modprobe = Modprobe(module)

    if modprobe.desired_state == "present" and not modprobe.module_loaded():
        modprobe.load_module()
    elif modprobe.desired_state == "absent" and modprobe.module_loaded():
        modprobe.unload_module()

    if modprobe.persistent == "present" and not (modprobe.module_is_loaded_persistently and modprobe.params_is_set):
        modprobe.load_module_permanent()
    elif modprobe.persistent == "absent" and (modprobe.module_is_loaded_persistently or modprobe.permanent_params):
        modprobe.unload_module_permanent()

    module.exit_json(**modprobe.result)


if __name__ == "__main__":
    main()
